Method for the in-situ treatment of hydrocarbonaceous materials

ABSTRACT

In-situ treatment of oil shale or other hydrocarbonaceous material by an inexpensive hot gaseous fluid, such as air or flue gas, as a heat transfer agent to volatilize kerogen or other hydrocarbonaceous matter and preferably also as a carrier of sufficient heat to crack and fissure the material to make it permeable to gas flow therethrough. Recovery of the volatilized hydrocarbonaceous material is through one or more bore holes remote from the location of hot gas introduction and aided by at least, but preferably, partial hydrogenation within a localized zone between location or locations of hot gas introduction and the one or more bore holes, preferably adjoining the latter.

United States Patent [191 J ustheim [4 1 Oct. 23, 1973 [75] Inventor:Clarence l. Justheim, Salt Lake City, Utah [73] Assignee: JustheimPetroleum Company, Salt Lake City, Utah [22] Filed: Dec. 27, 1971 [21]Appl. No.: 212,659

[52] US. Cl 166/261, 166/272, 166/247 [51] Int. Cl E21b 43/24 [58] Fieldof Search 166/303, 256, 259, 166/260, 261, 272, 247

[56] References Cited UNITED STATES PATENTS 3,692,110 9/1972 Grady166/259 2,595,979 5/1952 Pevere et al.... 166/303 3,285,335 11/1966Reistle, Jr. 166/303 X- 2,969,226 1/1961 Huntington 166/261 X 3,040,8096/1962 Pelzer 1'66/303 3,051,235 8/1962 Banks 166/261 3,084,919 4/1963Slater 166/261 X 3,102,588 9/1963 Fisher 166/261 3,521,709 7/1970Needham... 166/259 X 3,598,182 8/1971 .lustheim [66/247 3,237,689 3/1966Justheim 166/247 Primary ExaminerStephen J. Novosad Attorney-Philip A.Mallinckrodt et a1.

[57] ABSTRACT ln-situ treatment of oil shale or other hydrocarbonaceousmaterial by an inexpensive hot gaseous fluid, such as air or flue gas,as a heat transfer agent to volatilize kerogen or otherhydrocarbonaceous matter and preferably also as a carrier of sufficientheat to crack 7 and fissure the material to make it permeable to gasflow therethrough. Recovery of the volatilized hydrocarbonaceousmaterial is through one or more bore holes remote from the location ofhot gas introduction and aided by at least, but preferably, partialhydrogenation within a localized zone between location or 10- cations ofhot gas introduction and the one or more bore holes, preferablyadjoining the latter.

7 Claims, No Drawings METHOD FOR THE IN-SITU TREATMENT OFHYDROCARBONACEOUS MATERIALS BACKGROUND OF THE INVENTION 1. Field Thisinvention is in the well-developed field of in-situ treatment ofhydrocarbonaceous materials, especially oil'shales, for the recovery ofthe hydrocarbonaceous material contained therein.

2. State of the Art The distillation of oil shale has received muchattention for many years and has been carried out commercially tolimited extents in various parts of the world. ln-situ distillation hasbeen recognized as practical and perhaps the most economical approach tothe recovery of the great quantities of hydrocarbonaceous reserves knownto exist in the form of oil shale, much of which is represented by richoil shale deposits in areas of Colorado, Utah, and Wyoming of the UnitedStates of America. Insitu distillation has either been carried outcommercially or proposed by various methods of applying heat to theshale in its natural underground location. For example, electric heatershave been lowered into the bore holes and hydrocarbonaceous vapors drawnoff through other bore holes, sometimes with the aid of suction exertedthrough such other bore holes. In practically all instances, however,the well recognized lack of permeability of oil shale and of mostunderground deposits thereof has severely limited commercial operations.A variety of proposals have been made for fissuring and cracking oilshale deposit, e.g., by the use of explosives, the application of heatof exceptionally high temperature, and the solvent action of injectednatural gas, so fluid heat exchange media can be circulated through theunderground deposit and kerogen vapors recovered. It is also known toinject heated pure hydrogen gas into an underground deposit of oil shalefor heat exchange and permeabilitizing purposes, depending upon thetemperature employed, the hydrogen gas also effecting hydrogenation ofthe kerogen as and when released in vapor form, see my recently issuedU.S. Pat. No. 3,598,182 and my earlier U.S. Pat. No. 3,237,689, as wellas several U. S. and foreign patents cited therein.

SUMMARY OF THE INVENTIO In accordance with the present invention, arelatively cheap source of heat is utilized for diffusion throughout thearea of an underground deposit of oil shale to be treated at any giventime, such source including a gaseous fluid heat transfer agent (such asair or an inert gas) that is relatively inexpensive as compared to purehydrogen, thereby minimizing need for precautions that might otherwisebe deemed advisable against possible circulation losses of such fluid inthe deposit due to unanticipated crevices and the like of major extent.Combined with the admittedlyold use of such a relatively inexpensivefluid heat transfer medium is the injection of hydrogen gas into alocalized zone in the path of flow of such heat transfer medium andassociated vapors from the location or locations of introduction of theheat transfer medium to one or more vaporrecovery bore holes providedfor recovery of the volatilized kerogen. Preferably a single extractionbore hole is utilized, with the hydrogen injection zone adjoining suchbore hole. In this way, the volatilized kerogen is at least partiallyhydrogenated before extraction from the ground, to ecological andanti-pollution advantage as well as facilitating delivery of suchvolatilized kerogen values to the surface by reason of the chemicalchanges taking place due to the hydrogenation. Injection of the hydrogengas can be effected in any suitable manner, e.g., by one or more specialbore holes extending downwardly into the deposit from the surface orlaterally from any underground workroom that may be provided as part ofthe in-situ workings. If desired a special hydrogenation room may beprovided adjacent to or adjoining the vapor recovery bore hole intowhich the hydrogen is introduced and through which the kerogen vaporsare passed before being sent to the surface. Heating of theheat-transfer gas to desired temperatqres for kerogen distillationalone, or for that and the cracking and fissuring of the normallyimpervious oil shale, can be effected in any suitable manner, e.g., by anuclear reactor, a pebble heater, or some other source of heat at therequired temperature.

DETAILED DESCRIPTION OF BEST MODE PRESENTLY CONTEMPLATED It is believedunnecessary to illustrate any specific system for carrying out theinvention, since the use of bore holes, underground rooms, etc. in thein-situ treatment of oil shale for the volatilization and recovery ofits kerogen content are well detailed in the prior art and anyparticular deposit will require its own specific arrangement of theseworkings.

The best mode presently contemplated of carrying out the invention isthe heating of the air or other relatively inexpensive heat-exchange gasto requisite temperature, either above or below ground in a nuclearreactor, pebble heater, or other suitable heating device, and theinjection and circulation thereof through an underground deposit of oilshale, with recovery of the kerogen vapors, in essentially the mannershown in my previously referred to U.S. Pat. Nos. 3,237,689 and3,598,182. Combined with this is the injection, into the vicinity of therecovery bore hole or holes and in the path of flow of the vaporizedkerogen to be recovered, of hydrogen gas so as to effect at leastpartial hydrogenation of the vapors and a lightening thereof by reasonof the chemical reaction with respect to their oxygen, nitrogen, andsulfur constituency prior to rising of such vapors through the recoverybore holes, either because of their natural tendency to rise or becauseof suction applied to such recovery bore holes. As previously indicated,it is presently contemplated that a single recovery bore hole will beutilized, so as to concentrate the hydrogen into a relatively small zoneadjoining such bore hole. By utilizing one or more sets of paired heatinjection and recovery bore h'oles, cost of hydrogenation is kept to aminimum and permeability induced by use of ultra high temperature(2,000F.) beating medium is kept to a maximum.

In addition to the ecological and anti-pollution advantages of carryingout at least partial hydrogenation of the kerogen vapors underground,rather than at the surface, are the advantages derived by the characterof the vaporized kerogen product with respect to the facilitating of itsremoval from the underground location.

Optimum temperature to be maintained in the hydrogenation zone isbetween about 1,050F. and l,250"F., the higher temperatures between1,200F. and 1,250F. favoring hydrogasification of the surrounding shaleto yield greater mobility to the kerogen vapor product.

The hydrogen utilized can come from any source, including so-ca'lledsynthesis gas" derived from the oil shale itself, In the use of air asthe heat exchange gas, it is advantageous to utilize hydrogen inquantity such that it constitutes less than 4 percent or more than 74percent of any resulting air-hydrogen mixture, to avoid danger ofaccidental explosions and the need for special precautions to avoidconditions leading to ignition of the mixture. I z I Although specialemphasis has been placed herein on the treatment of oil shale by thedisclosed method, it should be realized that the method'is alsoapplicable to deposits of other hydrocarbonaceous materials, such asbituminous sands, coal, etc.

The present method has the advantage of considerable economy in thein-situ treatment of an underground deposit by the use of only partialhydrogenation for the purpose of facilitating recovery of thedistillation vapors.

Whereas this invention is here illustrated and described with respect tocertain preferred procedures thereof, it is to be understood that manyvariations are possible without departing from the inventive conceptsparticularly pointed out in the claims.

I claim: y

l. A method for the in-situ recovery of the hydrocarbonaceous content ofhydrocarbonaceous materials, comprising heating to at least distillingtemperature for the hydrocarbonaceous material concerned a heatexchangegas that is relatively inexpensive in comparison to substantially purehydrogen; injecting the soheated gas into an initial zone of anunderground depositof hydrocarbonaceous material to be distilled;flowing said gas through said underground deposit from said initial zoneto a product-withdrawal zone for vaporizing hydrocarbonaceous matter insaid deposit; in-

jecting hydrogen gas into a localized hydrogenation zone disposed in thepath of heat-exchange gas and vapor flow toward said product-withdrawalzone and in close adjacency-to the product-withdrawal zone, andmaintaining the temperature in the.hydrogenation zone between l,050 F.and l,250 F., said hydrogen gas being injected in an amounts'ufficientfor at least partial hydrogenation of hydrocarbonaceousvapors .to be withdrawn; and withdrawing from said productwithdrawalzone, at least partially hydrogenated hydrocarbonaceous vapors.

2. A method in accordance with claim 1, wherein the deposit ofhydrocarbonaceous material is oil shale.

3. A method in accordance with claim 2, wherein the oil shale in thedistillation area of the deposit is rendered permeable to the flow ofgas and vapors therethrough by heating the heat-exchange gas tosubstanquantity of hydrogen gas injected into the hydrogena-' tion zoneis such that the mixture of air and hydrogen gas contains less than 4percent or more than 74 percent hydrogen.

7. A method in accordance with claim 1, wherein at least one set ofpaired injection and vapor recovery bore holes are utilized forheat-exchange gas injection and hydrogenated vapor withdrawal,respectively.

2. A method in accordance with claim 1, wherein the deposit ofhydrocarbonaceous material is oil shale.
 3. A method in accordance withclaim 2, wherein the oil shale in the distillation area of the depositis rendered permeable to the flow of gas and vapors therethrough byheating the heat-exchange gas to substantially 2,000*F. prior toinjection thereof into the said area.
 4. A method in accordance withclaim 1, wherein the temperature maintained in the hydrogenation zone isbetween about 1,200*F. and 1,250*F.
 5. A method in accordance with claim1, wherein the heat-exchange gas is air.
 6. A method in accordance withclaim 5, wherein the quantity of hydrogen gas injected into thehydrogenation zone is such that the mixture of air and hydrogen gascontains less than 4 percent or more than 74 percent hydrogen.
 7. Amethod in accordance with claim 1, wherein at least one set of pairedinjection and vapor recovery bore holes are utilized for heat-exchangegas injection and hydrogenated vapor withdrawal, respectively.